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<head><meta charset="utf-8"><title>references to boxed trait objects · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html">references to boxed trait objects</a></h3>

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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136722716" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136722716">(Oct 29 2018 at 17:45)</a>:</h4>
<p><a href="https://stackoverflow.com/q/53049213/155423" target="_blank" title="https://stackoverflow.com/q/53049213/155423">Why is &amp;'a Box&lt;Trait&gt; treated as &amp;'a Box&lt;Trait + 'static&gt; and not &amp;'a Box&lt;Trait + 'a&gt;?</a></p>



<a name="136722787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136722787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136722787">(Oct 29 2018 at 17:46)</a>:</h4>
<p>I'm <em>guessing</em> that details changed during the implementation (again, I wish those were documented in the RFC after the fact).</p>



<a name="136781744"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136781744" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136781744">(Oct 30 2018 at 14:54)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> those rules were set by <a href="https://rust-lang.github.io/rfcs/1156-adjust-default-object-bounds.html" target="_blank" title="https://rust-lang.github.io/rfcs/1156-adjust-default-object-bounds.html">RFC 1156</a></p>
<p>Regarding updating RFCs, I think what you really wish is that we had an up-to-date and more complete language reference.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783146">(Oct 30 2018 at 15:17)</a>:</h4>
<p>That would also be nice. The problem is that RFCs exist but the reference doesn't, really.</p>



<a name="136783160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783160">(Oct 30 2018 at 15:17)</a>:</h4>
<p>Nobody likes writing documentation.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783175">(Oct 30 2018 at 15:18)</a>:</h4>
<p>But we require the RFC to be written, so it exists.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783256" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783256">(Oct 30 2018 at 15:18)</a>:</h4>
<p>theoretically we require docs to be written when a feature is "done",  but point me to some user-facing documentation that says <code>impl trait</code> exists <span class="emoji emoji-2639" title="sad">:sad:</span></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783416" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783416">(Oct 30 2018 at 15:20)</a>:</h4>
<p><a href="https://rust-lang-nursery.github.io/edition-guide/rust-2018/index.html" target="_blank" title="https://rust-lang-nursery.github.io/edition-guide/rust-2018/index.html">https://rust-lang-nursery.github.io/edition-guide/rust-2018/index.html</a></p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783440" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783440">(Oct 30 2018 at 15:20)</a>:</h4>
<p>but yes I think that addressing our "reference" needs is something I would like to see make it onto the Rust 2018 roadmap</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783670">(Oct 30 2018 at 15:23)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> the "problem" with the edition guide is that it's not on <a href="https://doc.rust-lang.org" target="_blank" title="https://doc.rust-lang.org">https://doc.rust-lang.org</a>. For many end-users, it's the same as an arbitrary blog.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136783998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136783998">(Oct 30 2018 at 15:28)</a>:</h4>
<p>maybe we should ping <span class="user-mention" data-user-id="116011">@Steve Klabnik</span> and fix that :)</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784001" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784001">(Oct 30 2018 at 15:28)</a>:</h4>
<p>and/or open a PR for that...</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784002">(Oct 30 2018 at 15:28)</a>:</h4>
<p>I'll raise the question</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784014" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784014">(Oct 30 2018 at 15:28)</a>:</h4>
<p>would be a good thing to have at least once we announce the edition</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784016">(Oct 30 2018 at 15:28)</a>:</h4>
<p>Wasn't that raised already?</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784021" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784021">(Oct 30 2018 at 15:28)</a>:</h4>
<p>For my PR that linked it in a diagnostic message.</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784034">(Oct 30 2018 at 15:29)</a>:</h4>
<p>I believe we moved it to a new location</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784036">(Oct 30 2018 at 15:29)</a>:</h4>
<p>I don't know if we were going to list it from that page or not</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784073">(Oct 30 2018 at 15:29)</a>:</h4>
<p>I read <span class="user-mention" data-user-id="116155">@Jake Goulding</span>'s message as "it isn't hosted under d.r-l.o" instead of "it isn't listed on the page at d.r-l.o"</p>



<a name="136784146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784146">(Oct 30 2018 at 15:30)</a>:</h4>
<p>ah, I know we had planned to change that URL, yes</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784164" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784164">(Oct 30 2018 at 15:30)</a>:</h4>
<p>steve says "that's the plan, but in a few weeks" (re: listing on <a href="http://doc.rust-lang.org" target="_blank" title="http://doc.rust-lang.org">doc.rust-lang.org</a>)</p>



<a name="136784211"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784211" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784211">(Oct 30 2018 at 15:31)</a>:</h4>
<blockquote>
<p>but in a few weeks</p>
</blockquote>
<p>I don't know how that plays with the fact that the docs there ride the trains... but "not my circus, not my monkeys"</p>



<a name="136784247"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784247" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784247">(Oct 30 2018 at 15:32)</a>:</h4>
<p>I guess they can merge to the master, release, and beta branches</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784290" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784290">(Oct 30 2018 at 15:32)</a>:</h4>
<p>I guess that's going to be backported to beta</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784296" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784296">(Oct 30 2018 at 15:32)</a>:</h4>
<p>well, in a few weeks it's just beta, not release</p>



<a name="136784339"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/references%20to%20boxed%20trait%20objects/near/136784339" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/references.20to.20boxed.20trait.20objects.html#136784339">(Oct 30 2018 at 15:33)</a>:</h4>
<p>well, it's a month and half until the next release, I think we can manage to backport it before 1.31</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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